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Medicine LibreTexts

9.1: Interpreting External Cues

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  • Learning Objectives

    • Explain various external cues and their relevance for animal internal balance

    An animal’s endocrine system controls body processes through the production, secretion, and regulation of hormones, which serve as chemical “messengers” functioning in cellular and organ activity and, ultimately, maintaining the body’s homeostasis. The endocrine system plays a role in growth, metabolism, and sexual development. In humans, common endocrine system diseases include thyroid disease and diabetes mellitus. In organisms that undergo metamorphosis, the process is controlled by the endocrine system. The transformation from tadpole to frog, for example, is complex and nuanced to adapt to specific environments and ecological circumstances (Figure \(\PageIndex{1}\)). The endocrine system also plays an important role in the timing of migration in animals that live in different regions in summer than in winter.

    Figure \(\PageIndex{1}\): The process of amphibian metamorphosis, as seen in the tadpole-to-frog stages shown here, is driven by hormones. (credit “tadpole”: modification of work by Brian Gratwicke).

    Exercise \(\PageIndex{1}\)

    How does interpretation of external environment impact animal survival or internal environment? Provide at least one example